A sheet processing apparatus for performing the processes of stapling, punching, and folding is disclosed in Patent Document 1.
The apparatus disclosed in Japanese Patent Application Publication No. 9-183558 switches a storage unit for temporarily storing image-formed sheets sequentially discharged from an image forming apparatus and a conveying path of sheets conveyed to the storage unit for each sheet size. The apparatus has a plurality of switching flaps. The switching flaps are driven by a solenoid. By use of such a constitution, the succeeding sheet, without getting into a sheet bundle already stacked on a processing tray, can be stacked at the uppermost position.
However, in the aforementioned apparatus, if the kinds of sheet sizes are increased, the number of flaps and solenoids for switching the sheet conveying path must be increased. Therefore, the cost and mounting man-hour are increased in correspondence with an increase in the number of components. Or, since there are many components equipped, a wide space is required, thus the apparatus increases in size.
Further, a plurality of sheet conveying paths are formed, so that to detect an abnormal system due to jamming of sheets conveyed on each sheet conveying path, for each conveying path, for example, for each flapper, a mechanical sensor is necessary to install for detecting passing of sheets, thus a problem arises that the cost and mounting man-hour are increased similarly.